Tubular electronic reactor component having an embedded electrode

ABSTRACT

An electronic reactor component is comprised of a tubular, monolithic, dielectric body in which is embedded a thin metallic electrode. The component is formed by bonding a metallic layer to a thin, flexible dielectric film or sheet, spirally winding the sheet and layer on a cylindrical form so that the metallic layer is coiled inside the coiled sheet, and firing the coiled sheet and layer to form the tubular monolithic, dielectric body in which the metallic electrode is embedded. A helical metallic layer may be bounded to the exterior of the dielectric body to constitute an inductor. The helical layer may be applied before or after firing the coiled sheet and internal metallic layer.

' United States Patent Mezey [451 Aug. 29, 1972 [54] TUBULAR ELECTRONIC REACTOR 2,827,601 3/1958 Garnzon ..317/249 T COMPONENT HAVING AN EMBEDDED 3,064,257 11/1962 Guest ..334/68 ELECTRODE 3,135,936 6/1964 Martin ..334/68 [72] Inventor: Frank G. Mezey, Centerport, FOREIGN PATENTS OR APPLICATIONS 11 v. V v .2 743,717 1/1956 Great Britain ..333/31C;

[73] Assignee: Victor Insetta, Old Westbury, NY.

. D Primary Examiner-Herman Karl Saalbach [22] Flled July 1970 Assistant Examiner-Saxfield ChatmonJr.

[21] App]. No.: 55,854 AttrneyEdward H. Loveman [52] U.S. Cl. ..333/82, 317/249, 317/251, [57] ABS CT 29/2542, 334/63, 333/31 C An electronic reactor component is comprised of a tu- 51 Int. Cl. ..H03h 7/30, H03j 3/22 bular, monolithic, dielectric y in which is [58] Field of Search ..317/251, 252, 249, 249 T; bcddcd a thin metallic clcctrcdc- Thc-ccmpcncnt is 333/31 (3 73 C 82; 334/63 formed by bonding a metallic layer to a thin, flexible dielectric film or sheet, spirally winding the sheet and [56] References Cited layer on a cylindrical form so that the-metallic layer is coiled inside the coiled sheet, and firing the coiled UNITED STATES PATENTS sheet and layer to form the tubular monolithic, dielec- 6,65 1 tric body in which the metallic electrode 18 embedded.

3 32 g an et a1 g: A helical metallic layer may be bounded to theiexteri- 2,998,840 9/1961 Davis 333/31 C or of the dielectric body to constitute an inductor. The

4 W195? a "5 X helical layer may be applied before or after firing the 3:274:466 9/1966 KinCaid IIIIIIIII....317/252 Sheet and internal metallic layer- 3,284,682 1 1/ 1966 Lippman ..317/252 X 9 Chims 12 Dram-g Figures 2,884,605 4/1959 Dubilier ..333/3l C 2,688,177 9/1954 Wagner ..317/249 T Patented Aug. 29, 1972 I 2 Sheets-Sheet 1 FIG.3

INVEXTOR. FRANK G. .1. MEZEY V ATTORNEY Patented Aug 29,

T 2 Sheets-Sheet a FIG. II

OUT

l l lllll l ll I I 111111 T. Mn

Y. INVENTOR. FRANK G. J. MEZEY ATTORNEY TUBULAR ELECTRONIC REACTOR COMPONENT HAVING AN EMBEDDED ELECTRODE This invention concerns improvements in electronic components, and more particularly concerns both a reactance component having a tubular dielectric member with an electrode embedded therein, and a method of fabricating such a reactance component.

l-leretofore it has been conventional to fabricate a tubular reactance assembly or metalizing a band on a rather thick cylindrical dielectric at one end of a stationary cylinder which houses an axially movable conductive piston. Structures of this type are typically shown in U.S. Pat. Nos. 2,922,093 and 3,366,697. This type of construction when used in a miniature trimmer capacitor presents many difficulties and objections. A principal objection is the difficulty of obtaining a large capacitance since the metalized band must be supported on a dielectric cylinder which substantially is thicker than the band. Other objections are the extremely limited range of adjustable reactance variation, difficulty of constructing the reactor in very small sizes, high cost of manufacture, reactance variation due to mechanical strain and vibration of the parts of the reactance components, etc. The present invention is directed to overcoming the above and other difl'rculties, disadvantages and objections of prior tubular reactors, and providing an improved reactance component and a new method of making such a component.

According to the invention an extremely thin metallic layer is deposited on a thin, flexible dielectric sheet. The sheet is spirally rolled on a rod or cylindrical mandrel so that metallic layer assumes a spiral form. The dielectric sheet is then fired, plasticized or set to form a homogeneous tube with the metallic layer embedded therein and defining a tubular electrode. The reactance component thus formed can then be assembled as a tubular stator with a rotor to form a trimmer capacitor.

The invention is especially intended for forming a 4 miniature, adjustable capacitor, however, it is also adapted to be made into a miniature inductancecapacitance circuit, or a tuned L-C circuit.

Accordingly, it is a primary object of the present invention to provide an improved solid state reactor.

Another object of the present invention is to provide a solid state reactor which is cylindrical in form and has a stator with a metallic electrode embedded therein.

Still another object of the present invention is to provide a method for manufacturing a solid state reactor of the type hereinabove mentioned.

These and other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which:

FIG. 1 is a longitudinal sectional view of a capacitor assembly embodying the invention;

FIG. 2 is an enlarged cross sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is an oblique plan view of a dielectric sheet and metallic layer shown at one stage in the process of making a tubular reactance component;

FIG. 4 is a longitudinal sectional view taken along line 4-4 of FIG. 3;

' If desired the bushing 22 may be tapered and cut cir- FIG. 5 rs a plan view of a tubular reactance component shown at another stage in the process of fabrication thereof;

FIG. 6 is a cross sectional view taken along line 6-6 of FIG. 5;

FIG. 7 is a longitudinal sectional view taken along line 7-7 of FIG. 6;

FIG. 8 is an oblique plan view similar to FIG. 3, showing another dielectric sheet and metallic layers used in forming a tubular L-C reactor component;

FIG. 9 is a plan view of the tubular L-C reactor component;

FIG. 10 is an enlarged fragmentary longitudinal sectional view taken along line 10-10 of FIG. 9;

FIG. 11 is a cross sectional view taken along line 11-11 ofFIG. l0; and

FIG. 12 is a diagram of the equivalent circuit of th reactor of FIGS. 10 and 1 1.

Referring now to the drawings wherein like reference characters designate like or corresponding parts throughout, there is illustrated in FIGS. 1 and 2 a capacitor assembly generally designated as reference numeral 20 of the panel mounting type. The capacitor 20 has an externally threaded bushing 22 which may be inserted in a hole in a panel and secured thereto by a nut 24 which is threaded on the bushing. The bushing has an annular flange 26 and a dielectric hollow cylindrical reactor generally designated by reference numeral 50 which embodies the invention. The reactor 50 is secured to the flange 26 by a metal band 30 held by solder 32. Within the reactor 50 is a spirally embedded electrode 54 and across the open end of reactor 50 is an electrically'conductive metallic end cap 62 which is in contact with the embedded electrode 54. On the outer free end of the reactor cylinder 50 is a metallic band or layer bonded to the cylinder and forming one terminal 34 of the capacitor assembly. Wire 35 is connected by solder 36 for terminal 34 for connection to an external circuit. The cylindrical reactor 50 and the electrode 34 form a stationary part or stator of the capacitor assembly 20.

Slidably mounted inside the reactor cylinder 50 is an electrically conductive metallic piston 28. The piston 28 at its right end, as view in FIG. 1, is in circumferential contact with the inner wall of the hollow cylindrical reactor 50. At the left end of piston 28 is a force fitted plug 55 which is secured to an axial threaded stud 56 engaged in a threaded axial bore 58 of the bushing 22. The piston 28 is advanced axially in reactor 50 by turning the stud 56 which has a slotted outer end 61 which may be engaged by a screwdriver. A nut 60 on I the stud may be tightened to lock the stud and thereby prevent longitudinal motion of the movable piston 28.

cumferentially to thereby substantially reduce end play of the stud 56 when it is threaded in bore 58. One end of a wire 65 may be connected by solder 63 to a terminal 64 on the bushing 22. It will be apparent that axial movement of the piston 28 with respect to electrode 54 varies the capacitance and capacitive reactance of the assembly 20.

The capacitor assembly 20 as shown in FIGS. 1 and 2 may be made in a very small size for use as a trimmer capacitor. The assembly may be made with a very large capacitance since the wall thickness between the embedded electrode and the piston 28 may be one-tenth as thick as the thickness between the inner and outer diameters of the reactor 50.

FIGS. 3-7 illustrate the steps in the fabrication of the cylindrical or tubular reactor 50. Referring now to FIG. 3 there is shown a rectangular dielectric sheet 79 which may be comprised of a green, unfired vitreous material, or a ceramic, glass, thermoplastic, or unset thermosetting plastic material, and upon which is applied a thin metallic film 54. This film may be silver, gold or the like applied by evaporation or other suitable techniques known in the art. The film 54' may have a thickness of about 0.3 mil while sheet 70 may have a thickness as small as 1.0 mil, whereby the wall thickness of the reactor 50 may be times thicker than the thickness of sheet 70. Sheet 70 and film 54' are quite flexible and may be wrapped spirally around a cylindrical rod or mandrel 75 shown in FIGS. 5, 6, and 7. The metallic film 54 is embedded between inner and outer turns of the sheet 70 and preferably defines a single spiral turn best shown in FIG. 6. It will be noted that the film 54 is initially disposed at one edge 73 of sheet 70 and is spaced from lateral edges 74, 76 but may be closer to the edge 76. After the sheet and film are wrapped around the rod 75 as shown in FIG. 7, it may be fired to integrate the several turns of the sheet 70 and form the tubular reactor 50 shown in FIG. 1 and 2. The wrapped sheet on the mandrel may be fired in such a way as to eliminate the edge 76 of the sheet shown in I FIG. 6, and be truly round as shown in FIG. 2, i.e., using a tubular fixture. Alternatively, after the firing the outer diameter may be ground to provide a smooth outer cylindrical surface. In any case after the firing is completed the cylinder will be a right cylindrical body with the electrode 54 embedded therein.

FIG. 8 shows another thin, flexible, dielectric sheet 80 onto which is applied a metallic layer 82 extending for the entire width of the sheet between edges 84, 86 but spaced from lateral edges 87 88. This sheet 80 may be wound on a rod or mandrel like the rod 75 so that the layer 82 assumes a spiral form. After firing the coiled sheet 80, spiral electrode 82a, will be embedded in a homogenous integrated tubular body 80a as shown in FIGS. 9, 10 and 11 and will extend along the full length of the body 80a. A thin metallic helical layer or stripe 90 may be bounded to the exterior of the body 80a along its full length. Wires 92, 94 may be connected to opposite ends of the conductive coil defined by a layer 90. A further wire 96 may be connected to the electrode 82a. This may be done by forming a slot 98 inside the body 80a to expose the electrode 82a as shown in FIG. 10.

FIG. 12 shows the equivalent circuit generally designated as reference numeral 166 of the electronic reactor 50a. The coiled layer 90 is an inductor and the electrode 82a is a capacitor electrode and in circuit constitute a electronic filter, tuned circuit, passive L-C network or serve as an input terminal of circuit 100 and the wire 94 will be an output terminal with the wire 96 acting as a grounded terminal. Reactor 50a may, if desired, be used with the piston 28 (FIG. 1) to form part of an adjustable reactor assembly having a fixed inductive reactance and variable capacitive reactance.

The reactors 50 and 50a have rugged, monolithic structures which insure dimensional stability, permanency of electrical parameters, and mechanical resistance to shock and vibration. They may be manufactured relatively inexpensively in ve small or miniature sizes for use in COI'IJUIICICIOI'I WI printed circuit, transistors, etc. They can have extended variable capacitance ranges from substantially zero up to rather high capacitance values.

It should be understood that the foregoing relates to only a preferred embodiment of the invention and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

The invention claimed is: 1. In a trimmer capacitor of the type wherein a piston moves longitudinally in a tubular monolithic homogeneous dielectric cylinder and wherein said piston serves as a first electrode, the improvement comprising a thin tubular metallic electrode, said electrode being wound radially in a substantially single spiral and embedded in said cylinder in coaxial alignment therewith; and

terminal means electrically connected to such electrode.

2. In a tubular trimmer capacitor as defined in claim 1, wherein said electrode is axially shorter than said cylinder and extends axially inward thereof from one end of said cylinder.

3. In a tubular trimmer capacitor as defined in claim 1, further comprising a helical metallic layer bonded to the exterior of said cylinder to constitute an inductor per se and a capacitance in conjunction with the electrode embedded in said cylinder.

4. In a tubular trimmer capacitor as defined in claim 3, wherein said helical layer extends axially substantially the full length of said cylinder, and wherein said electrode is axially substantially as long as said cylinder to extend from end to end thereof.

5. A method of making an electronic reactor component, comprising the steps of bonding a thin, metallic layer to a portion of a thin flexible dielectric sheet;

spirally coiling said sheet and layer radially to form a tube with a substantially single spiral metallic layer; and

firing said coiled sheet and layer to form a tubular,

monolithic, homogeneous dielectric body with said layer embedded therein in tubular form to constitute an electrode embedded in said body.

6. A method of making an electronic reactor component as defined in claim 5, comprising the further step of bonding a thin, helical conductive other layer on the exterior of said body to form an inductor thereon.

7. A method as defined in claim 5, comprising the further steps of connecting conductors to ends of said inductor and to said electrode.

8. A method as defined in claim 5, wherein said layer is substantially 1.0 mil thick, and wherein the wall of said tubular body is substantially 10.0 mil thick.

9. A method as defined in claim 5 wherein said sheet and layer are both rectangular in form, and wherein said layer is narrower than said sheet and spaced from opposite lateral edges of the sheet when bonded thereto. 

1. In a trimmer capacitor of the type wherein a piston moves longitudinally in a tubular monolithic homogeneous dielectric cylinder and wherein said piston serves as a first electrode, the improvement comprising a thin tubular metallic electrode, said electrode being wound radially in a substantially single spiral and embedded in said cylinder in coaxial alignment therewith; and terminal means electrically connected to such electrode.
 2. In a tubular trimmer capacitor as defined in claim 1, wherein said electrode is axially shorter than said cylinder and extends axially inward thereof from one end of said cylinder.
 3. In a tubular trimmer capacitor as defined in claim 1, further comprising a helical metallic layer bonded to the exterior of said cylinder to constitute an inductor per se and a capacitance in conjunction with the electrode embedded in said cylinder.
 4. In a tubular trimmer capacitor as defined in claim 3, wherein said helical layer extends axially substantially the full length of said cylinder, and wherein said electrode is axially substantially as long as said cylinder to extend from end to end thereof.
 5. A method of making an electronic reactor component, comprising the steps of bonding a thin, metallic layer to a portion of a thin flexible dielectric sheet; spirally coiling said sheet and layer radially to form a tube with a substantially single spiral metallic layer; and firing said coiled sheet and layer to form a tubular, monolithic, homogeneous dielectric body with said layer embedded therein in tubular form to constitute an electrode embedded in said body.
 6. A method of making an electronic reactor component as defined in claim 5, comprising the further step of bonding a thin, helical conductive other layer on the exterior of said body to form an inductor thereon.
 7. A method as defined in claim 5, comprising the further steps of connecting conductors to ends of said inductor and to said electrode.
 8. A method as defined in claim 5, wherein said layer is substantially 1.0 mil thick, and wherein the wall of said tubular body is substantially 10.0 mil thick.
 9. A method as defined in claim 5 wherein said sheet and layer are both rectangular in form, and wherein said layer is narrower than said sheet and spaced from opposite lateral edges of the sheet when bonded thereto. 